In these years, medical diagnostic imaging apparatuses have come into use, which are configured to collect information about the inside of a subject and to generate a medical image by imaging the inside of the subject on the basis of the collected information. For example, X-ray computed tomography (CT) apparatuses, magnetic resonance imaging (MRI) apparatuses and the like are the medical diagnostic imaging apparatuses. A generated medical image is displayed on, for example, a medical image display apparatus connected to the network.
Most cases of atrial fibrillation as a type of cardiac arrhythmia are considered to stem from the pulmonary veins of the left atrium of the heart. As one kind of treatment of atrial fibrillation, a so-called ablation treatment is carried out for the purpose of returning the flow of an electrical signal for causing the heart to beat to normalcy. In the ablation treatment, a part of the heart which disrupts the transmission of the electrical signal or its periphery is burned.
For the ablation treatment, a method using a balloon catheter has been employed in these years. The balloon catheter is originally used to restore the flow of blood in the coronary artery, peripheral blood vessel, or the like by treatment of dilating a stenosis site, blocked site or the like in the vascular lumen (see Japanese Patent Application Publication No. 2010-193956). However, in the ablation treatment, the balloon catheter is used for: heating a fluid filled in the balloon; and burning a target area or its periphery with heat. The ablation treatment method using the balloon catheter is advantageous over another ablation treatment method of directly burning a target area, in that an electric current for generating the heat for burning is not directly applied to the target area, and because the burning depth can be anticipated.
In a case where a balloon catheter disclosed in Japanese patent Application Publication No. 2010-193956 below described is used for the ablation treatment, specifically, the leading end of the catheter is inserted into the pulmonary vein of the left atrium of the heart, and the balloon is brought into pressure contact with the boundary between the pulmonary vein and the left atrium of the heart. Thereby, the boundary region is burned.
In this process, it is important that the balloon be completely brought into pressure contact with the tissues in the boundary region which needs to be burned (hereinafter referred to a “treatment target area”). To this end, the conventional ablation treatment judges that the balloon is in pressure contact with the treatment target area by: injecting the contrast medium from the front end of the catheter with the balloon in pressure contact with the treatment target area; and confirming by use of an X-ray machine that no portion of the contrast medium flows out of the pulmonary vein into the left atrium of the heart.
However, in the ablation treatment using the balloon, it is possible to check whether the balloon is in pressure contact with the periphery of the opening of the pulmonary vein of the left atrium of the heart, but it is impossible to check a pressure-contact degree such as a pressure contact area of the balloon as a whole. For this reason, it is impossible to exactly recognize a burning area in the ablation treatment.
In addition, in the ablation treatment, the amount of contrast medium applied to the subject is increased because whether or not the pressure contact occurs is checked by using the contrast medium in the ablation treatment. As a result, the ablation treatment may cause a harmful influence of raising the probability of the side-effects of the contrast medium compared with a non-ablation treatment.